Final Exam Flashcards

1
Q

who is Robert Hooke?

A

-invented first microscope
-analyzed cork bark and saw cells
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2
Q

who is Anthony Van Leeuwenhock

A

-wealthy merchant who worked with glass
-created high quality lenses with which 300x magnification was possible
-was protists from algae
-saw bacteria from tooth plaque
-

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3
Q

what happened in 1830?

A

-compound microscope was invented
-improved magnification and resolution

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4
Q

who is Robert Brown?

A

-botanist
-saw that every plant cel contained a round structure (nucleus)

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5
Q

who is Matthias Scheilden?

A

-botanist
-all plant tissue is composed of cells
-embryonic plant arose from single cell

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6
Q

who is Theodor Schwann?

A

-zoologist
-similar observations as brown and scheilden but in animal cells
-formulated the cell theory

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7
Q

what is the cell theory?

A

-all organisms consist of one or more cells
-the cell is the basic unit of structure for all organisms
-all cells arise only from pre-existing cells

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8
Q

generally explain the secretory pathway

A

Rough ER
-synthesis of proteins
Golgi
-collection, packaging, distribution of proteins
Lysosomes
-“cell stomach”
-can fuse with vesicles
-material brought into cell by phagocytosis

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9
Q

what is the endosymbiont theory?

A

-mitochondria and chloroplasts were once prokaryotes that were engulfed by larger cells
-have double membrane and their own genome
-have their own ribosomes
-genetically similar to parent bacteria rather than eukaryotic cell

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10
Q

what is a scientific fact?

A

-based on observations and experiments
-attempt to explain our current, best explanation
-valid until replaced by better facts with careful observations and experiments

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11
Q

what is the scientific method

A

-make observations
-make a hypothesis based on observations
-make predictions based on the hypothesis
-further testing and observations of hypothesis adds strength to it
-interpret results to see if hypothesis is true

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12
Q

what is a theory?

A

-Once the hypothesis has been greatly tested and there is enough evidence to support it strongly
-Once it is accepted by most scientists the hypothesis is now a theory
-E.g. Germ theory, evolution, cell theory -A law is more solid than a theory (there is no doubt that it is true)
-E.g. Law of gravity, thermodynamics, behaviour of gases
-Biologists are conservative in using the term “law”

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13
Q

which strand of DNA is transcribed

A

the template strand, read in a 3’ to 5’ direction

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14
Q

how are the bases bonded together?

A

-phosphodiester bonds form in each strand (nucleoside triphosphate loses 2 phosphates and bonds to OH link)
-hydrogen bonds between the strands at each base

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15
Q

how is DNA transcribed?

A

-RNA polymerase
-binds to DNA at promotor sequence and unwinds it (sigma factor recognizes sequence)
-sigma factor finds the -10 and -35 boxes and binds to them to properly orient the RNA polymerase holoenzyme
-sigma factor is released after RNA synthesis begins
-ribonucleoside triphosphates come in through the uptake channel and match with the template strand
-then mRNA leaves and the DNA is wound back up with its other strand

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16
Q

how is transcription terminated in bacteria?

A

-polymerase termination signal
-this codes for RNA that folds back up on itself (hairpin loop)
-this disrupts the transcription complex and polymerase releases RNA transcript and DNA template

17
Q

how is transcription different in eukaryotes?

A

-DNA is tightly packed around histones
-3 types of RNA polymerase
-promotors are more complex
-RNApol II recognizes many promotors including the TATA box which is 30 bp upstream
-general transcription factors must assemble at promotor along with RNApol
-mRNA is further processed before leaving the nucleus

18
Q

initiation of transcription in eukaryotes

A

-TATA box recognized by TATA binding protein (TBP)
-TBP is a subunit of a transcription factor (TFIID)
-TFIID binding allows other transcription factors to bind and form the transcription initiation complex
-TFIIH pries the double helix apart at the transcription start point

19
Q

modifications after transcription

A

-modifications carried out by enzymes that ride on RNApol II
-nRNA 5’ G cap
-poly-A tail on 3’ end
-introns are taken out (splicing) (occirs while still being transcribed)

20
Q

how does splicing occur?

A

-intron sequence forms a loop by taking a point in the intron and attaching it to the 5’ end
-cut end on 5’ end forms a covalent bond with the ribose sugar group on 3’ end
-lariat (loop) is degraded
-carried out by spliceosomes

21
Q

what are spliceosomes

A

-consists of 5 small nuclear ribonucleic particles (snRNPs)
-considered ribozyme

22
Q

what are the advantages of RNA splicing?

A

-can create different proteins from the same gene/ primary transcript

23
Q

what are the disadvantages of RNA splicing?

A

-more steps
-more work
-more opportunity for error
-mutations of splice can result in: loss of exons, inclusion of introns, and shift in location of splice

24
Q

what happens after the modifications?

A

-cap and poly-A tail are marked by proteins
-group of proteins (exon junction complex or EJC) binds to spliced mRNA
-mRNA transported out of nuclear pore into cytoplasm